Contract of Defiance by Tammy Salyer (Spectras Arise Trilogy)

In a few hundred years, the Algol system becomes humanity's new home. The question is: is it a better one? When a crew of arms smugglers botches their latest job, Corps-deserter and crewmember, Aly Erikson, is separated from her brother, the only person she can trust, and left behind to fight for her life. In the aftermath, as she tries to piece together what happened, a crew of roughneck settlers pressgang her into a dangerous mission in the heart of Corps territory. Time is running out to get back everything she's lost: her crew, her brother, and her options. But no one is taking her gun.